The present invention is directed to keyboards associated with a data terminal device and more particularly to a system for generating a tone signal representing the actuation of a key portion of a membrane-type or other types of keyboards that operate without tactile feedback.
With the advent of computers, hand-held calculators and the like, electronic keyboards have been developed in which the keyboard switches take the form of two membrane-type members making contact to provide a signal indicating the key position that has been actuated. The signal thus generated is normally decoded to generate binary data signals representing the actuated key. Prior mechanical type keyboards associated with cash registers or the like were constructed of key switch mechanisms which, when actuated, generated a feedback tone or click indicating the closing of the switch. With membrane type electronic keyboards, such audio feedback is not present. In order to provide such feedback, audio generators have been incorporated into keyboards to provide an audio feedback tone representing the click sound which occurs upon depressing a portion of the keyboard. The loudness control of such audio generators was found in either a switch or a rheostat. The use of this type of volume control was found to be inadequate to provide the required volume levels where the noise environment in which the data terminal was used and the hearing capacity of the terminal operators varies.
It is therefore a principal object of this invention to provide an electronic keyboard associated with a data terminal device having an audio feedback system which can be selectively programmed by the terminal operator to provide a plurality of volume levels to compensate for the noise environment in which the data terminal is used and the hearing capacity of the operator.
It is another object of this invention to control the programming of such an audio feedback system utilizing the key members of the keyboard.